Graphene is a single planar sheet of sp2 bonded carbon atoms, and has properties of great electrical conductivity, great thermal conductivity, high transparence, and high mechanical strength in an x-y plane.
Generally, graphene may be formed by solid phase techniques or liquid phase techniques. The liquid phase techniques include chemical exfoliation and electrochemical exfoliation.
Electrochemical exfoliation is carried out by steps of: disposing a graphite material in an electrolyte; applying an electric field to the electrolyte such that ions intercalate into layers of the graphite material to exfoliate the graphite material.
However, reaction yield of electrochemical exfoliation is only around 5% to 8%, leaving ample room for improvement in the art.